Michael Kuryla Jr., one of 317 sailors who survived the sinking of the ill-fated Navy cruiser Indianapolis during World War II and later bonded with other activists to exonerate their ship's captain, died of cancer Oct. 3 at his home in Bartlett, Ill. He was 84.

Kuryla found strength from his fellow stranded Navy comrades floating in shark-infested waters of the Philippine Sea for nearly five days in 1945. Their ship, the cruiser Indianapolis, sank in just 12 minutes after being hit by two Japanese torpedoes shortly after delivering the atomic bomb that would level Hiroshima.

Three hundred of Kuryla's shipmates died that day when the ship went down. Nine hundred were left floating in only life preservers, facing a harsh sun and sharks, as three SOS calls went unanswered.

An anti-submarine plane spotted them four days after the attack, and only 317 survived when help finally arrived.

Kuryla, who for years was reticent to share details of the ordeal unless asked, found his voice -- and strength -- once again from his comrades. He and other Indianapolis survivors came together to help clear the name of Capt. Charles B. McVay III, who they believed was unfairly court-martialed and blamed for putting the ship in harm's way.

"They made numerous trips to Washington, D.C., to meet with government officials to speak on his behalf," said Kuryla's son, Michael.

"It became his life mission," his son said. "He traveled the country speaking to schoolchildren and honoring the memory of his lost shipmates."

Born in 1925 and reared on Chicago's North Side, Kuryla was a junior in high school when he enlisted in the Navy and later began serving aboard the Indianapolis. He participated in several major battles at sea before the deadly attack on his ship in the Philippine Sea on July 30, 1945.

"So many died from just drinking the salt water," his son said. "My father was rescued, but for years he suffered nightmares and felt the guilt of being a survivor."

After the war, Kuryla returned to Chicago and in 1952 married his future wife of 57 years, Lorain. The family settled in Hillside, Ill., where he operated a construction and painting business, family members said. For several years in the 1980s, Kuryla also served as Hillside's public works director.

For many years, Kuryla also held a leadership role in the USS Indianapolis Survivors Organization. In the early 1990s, the group raised money to build the USS Indianapolis Memorial -- which was dedicated as a national landmark in 1995 -- in downtown Indianapolis. According to the Indianapolis Star, there were 67 Indianapolis survivors as of June.

In addition to his wife and son, Kuryla is survived by two daughters, Diane Schnurstein and Jody Bierzychudek; a brother; two sisters; and five grandchildren.